Skip to main content

Full text of "Handbook Of Chemical Engineering - I"

See other formats


THE TRANSPORTATION OF LIQUIDS                      139
(6) Percentage of slip [100 (Item 22o-Item 22)/Item 22a.]..........per cent
(c)  Leakage of pump1........................................   ......gal.
(d)  Total gallons of water discharged, by calculation from plunger dis-
placement, corrected for leakage................................gal.
(e)  Total weight of water discharged, as measured........................Ib.
(/) Total weight of water discharged, by calculation from plunger displacement, corrected for leakage.....................................Ib.
HOURLY QUANTITIES
(23)  Total water fed to boilers or drawn from surface condenser per hour........Ib.
(24)  Total dry steam consumed for all purposes per hour (Item 21 -r- Item 8) ... .Ib.
(25)  Steam consumed per hour for all purposes foreign to main engine...........Ib.
(26)  Dry steam consumed by engine or turbine per hour (Item 24  Item 25)... .Ib.
(a) Circulating water supplied to condenser per hour....................Ib.
(27)  Weight of water discharged per hour, by measurement....................Ib.
(a) Weight of water discharged per hour, calculated from plunger displacement, corrected...............................................Ib.
HOUELY HEAT DATA
28) Heat units consumed by engine or turbine per hour [Item 26 X (total heat of 1 Ib. of steam at pressure of Item 9, less heat in 1 Ib. of water at temperature of Item 14)]....................................B.t.u.
INDICATOR DIAGRAMS
(29) Mean effective pressure, each steam cylinder.............................Ib.
(a) Mean effective pressure, each water cylinder, if any..................Ib.
SPEED AND STROKE
(3 0) Revolutions per minute.............................................r.p.m
(a) Number of single strokes per min.....(6) Average length of stroke......ft
POWER
(31)  Indicated horsepower developed.......................................i.hp-
(a) Brake horsepower consumed by pump..............................hp.
(32)  Water horsepower2....................................................hp.
(33)  Friction horsepower (Item 31 - Item 32)................................hp.
(34)  Percentage of indicated horsepower lost in friction..................per cent
1 Leakage of an inside plunger may best be determined by removing the cylinder head and bolting a wide board over the lower part of cylinder end to form a dam, in which an overflow pipe is inserted. The plunger is then blocked (preferably at some intermediate point of the stroke), and water admitted behind it from the force main, at full pressure.    The leakage is caught from the overflow pipe in barrels and measured.    If possible, tests should be made with the plunger in various positions.    If the cylinder head is difficult to remove, the leakage may be measured through one of the openings provided for inspecting the suction valves.    Any leakage of valves should be remedied before making the plunger test.    Leakage of discharge valves will be shown by water passing down into the empty cylinder at either end when they are under pressure; and of suction valves by the disappearance of water which covers them.    If valve leakage is found which cannot be remedied, the water thus lost should also be measured. One method consists in measuring the amount of water required to maintain a certain pressure in the pump cylinder when this is introduced through a pipe temporarily erected, no water being allowed to enter through the discharge valves of the pump.
2 Water hp. = ft.-lb. of work per min. -^ 33,000.    Work done per min., ft.-Ib. = net area of plunger A (sq. in.) X total head #, Ib. per sq. in. ( = pressure on force main +   pressure on suction main + pressure equivalent to the head or vertical distance between the centers of the two gages) X length of stroke S, ft, X number of single strokes per min., N; corrected for leakage.